wait_for_transaction

THE RISK

Low Risk

Why wait_for_transaction needs a policy

This tool only monitors/polls the blockchain network to check transaction status until it is confirmed. It does not initiate any transaction, move funds, or modify any state — it is purely a read/observation operation. The polling itself has no side effects on the blockchain.

From the tool's definition Wait for a transaction to be confirmed (mined). Polls the network until confirmation.

Documented attack patterns abuse exactly the kind of access wait_for_transaction gives an agent:

POLICY

How to control wait_for_transaction

PolicyLayer is an MCP gateway — it sits between your AI agents and EVM MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for wait_for_transaction:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "wait_for_transaction": {}
  }
}

wait_for_transaction is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register EVM MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

CAP THIS TOOL →

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EXPLORE

Related tools and policies

More EVM MCP Server tools

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about wait_for_transaction

What does the wait_for_transaction tool do? +

Wait for a transaction to be confirmed (mined). Polls the network until confirmation. It is categorised as a Read tool in the EVM MCP Server MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on wait_for_transaction? +

Register the EVM MCP Server MCP server in PolicyLayer and add a rule for wait_for_transaction: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches EVM MCP Server. Nothing to install.

What risk level is wait_for_transaction? +

wait_for_transaction is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit wait_for_transaction? +

Yes. Add a rate_limit block to the wait_for_transaction rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block wait_for_transaction completely? +

Set action: deny in the PolicyLayer policy for wait_for_transaction. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides wait_for_transaction? +

wait_for_transaction is provided by the EVM MCP Server MCP server (mcpdotdirect/evm-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every EVM MCP Server tool call.

Start from EVM MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →